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Open Access Highly Accessed Research article

Green tea polyphenols supplementation and Tai Chi exercise for postmenopausal osteopenic women: safety and quality of life report

Chwan-Li Shen123*, Ming-Chien Chyu1456, Barbara C Pence1, James K Yeh7, Yan Zhang28, Carol K Felton9, Susan Doctolero10 and Jia-Sheng Wang11

Author Affiliations

1 Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

2 Laura W. Bush Institute for Women's Health, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

3 Department of Laboratory Science and Primary Care, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

4 Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA

5 Department of Health, Exercise, and Sport Sciences, Texas Tech University, Lubbock, Texas, USA

6 Graduate Healthcare Engineering Option, Texas Tech University, Lubbock, Texas, USA

7 Applied Bench Core Laboratory, Winthrop-University Hospital, Mineola, New York, USA

8 Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

9 Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

10 Clinical Research Center, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

11 Department of Environmental Health Science, University of Georgia, Athens, Georgia, USA

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BMC Complementary and Alternative Medicine 2010, 10:76  doi:10.1186/1472-6882-10-76

Published: 9 December 2010

Abstract

Background

Evidence suggests that both green tea polyphenols (GTP) and Tai Chi (TC) exercise may benefit bone health in osteopenic women. However, their safety in this population has never been systematically investigated. In particular, there have been hepatotoxicity concerns related to green tea extract. This study was to evaluate the safety of 24 weeks of GTP supplementation combined with TC exercise in postmenopausal osteopenic women, along with effects on quality of life in this population.

Methods

171 postmenopausal women with osteopenia were randomly assigned to 4 treatment arms for 24 weeks: (1) Placebo (500 mg starch/day), (2) GTP (500 mg GTP/day), (3) Placebo + TC (placebo plus TC training at 60 min/session, 3 sessions/week), and (4) GTP + TC (GTP plus TC training). Safety was examined by assessing liver enzymes (aspartate aminotransferase, alanine aminotransferase), alkaline phosphatase, and total bilirubin at baseline and every 4 weeks. Kidney function (urea nitrogen and creatinine), calcium, and inorganic phosphorus were also assessed at the same times. Qualify of life using SF-36 questionnaire was evaluated at baseline, 12, and 24 weeks. A mixed model of repeated measures ANOVA was applied for analysis.

Results

150 subjects completed the study (12% attrition rate). The compliance rates for study agents and TC exercise were 89% and 83%, respectively. Neither GTP supplementation nor TC exercise affected liver or kidney function parameters throughout the study. No adverse event due to study treatment was reported by the participants. TC exercise significantly improved the scores for role-emotional and mental health of subjects, while no effect on quality of life was observed due to GTP supplementation.

Conclusions

GTP at a dose of 500 mg/day and/or TC exercise at 3 hr/week for 24 weeks appear to be safe in postmenopausal osteopenic women, particularly in terms of liver and kidney functions. TC exercise for 24 weeks (3 hr/wk) significantly improved quality of life in terms of role-emotional and mental health in these subjects. ClinicalTrials.gov identifier: NCT00625391.